Southern California’s section of the San Andreas Fault is “locked, loaded and ready to roll,” a leading earthquake scientist said Wednesday at the National Earthquake Conference in Long Beach.

The San Andreas Fault is one of California’s most dangerous, and is the state’s longest fault. Yet for Southern California, the last big earthquake to strike the southern San Andreas was in 1857, when a magnitude 7.9 earthquake ruptured an astonishing 185 miles between Monterey County and the San Gabriel Mountains near Los Angeles.

It has been quiet since then – too quiet, said Thomas Jordan, director of the Southern California Earthquake Center. Source